Internal combustion engine with controlled ignition and direct injection

Abstract

An internal combustion engine with controlled ignition and direct ignition. In the internal combustion engine at least one intake duct can generate in a cylinder a flow referred to as “tumble”, at least for certain engine operating phases. Further, a fuel injector is implanted so as to emerge in the cylinder such that the fuel jet tends to be intercepted by the part of the flow circulating in the direction opposite to that of the jet which is directed towards the spark plug.

What is claimed is:  
     
       1. An internal combustion engine with controlled ignition and direct injection, 
       of the type in which a cylinder is bounded axially at the top by a lower face of a cylinder head, into which there open, each via a corresponding valve, at least one intake duct and at least one exhaust duct, the intake valves and exhaust valves being provided respectively on opposite sides of a reference plane containing the axis of the cylinder and bounding an intake side and an exhaust side of the cylinder,  
       characterized in that at least one of the intake ducts is adapted to create in the cylinder, at least during certain stages of operation of the engine, a tumble flow in which the gases contained in the cylinder are caused to move rotationally around an axis perpendicular to the cylinder axis and parallel to the reference plane, and in that a fuel injector is located in such a manner that it enters the lower face of the cylinder head such that the fuel jet tends to be intercepted by the portion of the flow circulating in the sense opposite to that of the jet and directed toward a spark plug, and  
       characterized in that the cylinder is axially bounded at the bottom by a piston, an upper face of which is provided with a cavity which is disposed eccentrically relative to a first side of the reference plane, and in that the injector is located on the opposite side to inject the fuel toward the cavity.  
     
     
       2. An engine according to  claim 1 , characterized in that the injector is located substantially at the center of the lower face of the cylinder head. 
     
     
       3. An engine according to  claim 1 , characterized in that the injector is located in such a manner that it enters an external radial portion of the lower face of the cylinder head. 
     
     
       4. An engine according to  claim 1 , characterized in that the cavity is provided with a lateral well element which, in the vicinity of the axis, has a large slope along the direction of the axis of the cylinder. 
     
     
       5. An engine according to  claim 4 , characterized in that the piston is provided with a channel, which is hollowed out in the upper face of the side opposite the cavity, which is oriented parallel to the injection jet of the injector, and which opens into the lateral wall of the cavity. 
     
     
       6. An engine according to  claim 4 , characterized in that the upper face of the piston is provided, on the side opposite the cavity, with a boss whose shape is substantially complementary to that of the portion facing the lower wall of the cylinder head, in order to cause a gas-flushing effect during arrival of the piston at top dead center. 
     
     
       7. An engine according to  claim 1 , characterized in that the lower face of the cylinder head has the shape of a roof with two inclined spans, which are bounded by a top ridge contained in the reference plane. 
     
     
       8. An internal combustion engine with controlled ignition and direct injection, 
       of the type in which a cylinder is bounded axially at the top by a lower face of a cylinder head, into which there open, each via a corresponding valve, at least one intake duct and at least one exhaust duct, the intake valves and exhaust valves being provided respectively on opposite sides of a reference plane containing the axis of the cylinder and bounding an intake side and an exhaust side of the cylinder,  
       characterized in that at least one of the intake ducts is adapted to create in the cylinder, at least during certain stages of operation of the engine, a tumble flow in which the gases contained in the cylinder are caused to move rotationally around an axis perpendicular to the cylinder axis and parallel to the reference plane, and in that a fuel injector is located in such a manner that it enters the lower face of the cylinder head such that the fuel jet tends to be intercepted by the portion of the flow circulating in the sense opposite to that of the jet and directed toward a spark plug, and  
       characterized in that the gases contained in the cylinder are caused to assume a direct tumble movement, in that a concave cavity is eccentrically disposed on the exhaust side of the reference plane, and in that the injector is located such that it enters the lower face of the cylinder head on the intake side.  
     
     
       9. An internal combustion engine with controlled ignition and direct injection, 
       of the type in which a cylinder is bounded axially at the top by a lower face of a cylinder head, into which there open, each via a corresponding valve, at least one intake duct and at least one exhaust duct, the intake valves and exhaust valves being provided respectively on opposite sides of a reference plane containing the axis of the cylinder and bounding an intake side and an exhaust side of the cylinder,  
       characterized in that at least one of the intake ducts is adapted to create in the cylinder, at least during certain stages of operation of the engine, a tumble flow in which the gases contained in the cylinder are caused to move rotationally around an axis perpendicular to the cylinder axis and parallel to the reference plane, and in that a fuel injector is located in such a manner that it enters the lower face of the cylinder head such that the fuel jet tends to be intercepted by the portion of the flow circulating in the sense opposite to that of the jet and directed toward a spark plug, and  
       characterized in that the gases contained in the cylinder are caused to assume an inverse tumble movement, in that the concave cavity is eccentrically disposed on the intake side of the reference plane, and in that the injector is located such that it enters the lower face of the cylinder head on the exhaust side.  
     
     
       10. An engine according to  claim 9 , characterized in that the cylinder is provided with a single exhaust valve, which is offset transversely relative to the cylinder axis along a first sense of a direction parallel to the reference plane, and in that the injector is offset along an opposite sense of the said direction parallel to the reference plane. 
     
     
       11. An internal combustion engine comprising: 
       a cylinder bounded axially at a top by a lower face of a cylinder head, said cylinder having an axis;  
       at least one intake duct connected to said cylinder, said at least one intake duct having an intake valve;  
       at least one exhaust duct connected to said cylinder, said at least one exhaust duct having an exhaust valve, said intake valve and said exhaust valve being provided on opposite sides of a reference plane containing said axis of said cylinder, said reference plane bounding an intake side and an exhaust side of said cylinder; and  
       a fuel injector configured to inject fuel into said cylinder,  
       wherein said at least one intake duct is adapted to create in said cylinder a tumble flow in which gases contained in said cylinder are caused to move rotationally around an axis perpendicular to said axis of said cylinder and parallel to said reference plane,  
       wherein said cylinder is axially bounded at a bottom by a piston, said piston having an upper face that is provided with a cavity, said cavity being disposed eccentrically relative said reference plane, and  
       wherein said fuel injector is located on a side of said reference plane opposite to said cavity to inject fuel toward said cavity.